Teac A-6010GSL User manual

TEAC
22232
STEREO
TAPE
DECK
®
SERVICE
MANUAL
TEAC
CORPORATION
U.S.
DISTRIBUTOR:
TEAC
corpora
ron
oF
AMERICA
7733 TELEGRAPH ROAD
SALES
OFFICE:
SHINQURU
BUILDING
MONTEBELLO,
CALIFORNIA
90640
1-8-1,
NISHI-SHINJUKU,
SHINJUKU,
TOKYO
U.S.A.
TEAC
HONGKONG
LIMITED
ROOM
NO.
1105
EUROPEAN
DISTRIBUTOR:
TEAC
EUROPE
B.V.
MAIN
OFFICE:
MELBOURNE
PLAZA,
33
QUEEN'S
ROAD
C.
KABELWEG
45-47,
AMSTERDAM-W.
2,
HONG KONG
HOLLAND
MT6012E100
:
er
pfuivruin'{Waakan
pe7uz
oes

To make a handy labling tab from
a portion of the back cover:
1.
Ba
Cut along the dotted Jines and
fold back.
Re-assemble the binder and
close it with the tab sticking
out.
. Bend the tab over the front
cover.
Cut off the above label and
stick it on the tab.

:
1. GENERAL DESCRIPTION
The TEAC A-6010GSL is a three motors, solenoid operated, four high
density ferrite heads provided (forward; erase, record, playback and
reverse playback). Dual system automatic reverse, phase sensing sig-
nal or foil operated.
The AR-70GSL preamplifier circuits use IC and silicon transistors.
Independent circuits are provided for recording, monitoring, VU meter
amplifier and playback functions. Electrical assembly provides two
level bias selector for conventioanl and low noise/high out tapes, dual
scale VU meter, meter level switch for optimum recording accuracy with
any type recording tape. Full MIC/LINE mixing capability with individ-
ual level controls.
This service manual provides adjustment and alignment procedures, sche-
matic diagram, parts replacement information and the proper procedures
for obtaining necessary repair parts.
If adjustments or repair procedures are not clear or seem difficult to
accomplish or should you desire more detailed technical information,
please contact your nearest TEAC dealer, TEAC Corporation or affiliated
corporations, addresses of which are printed in this manual.
— INDEX
1. GENERAL DESCRIPTION
2. SERVICE DATA
3. EQUIPMENT REQUIRED
4. PARTIAL DISASSEMBLY
5. HEAD MECHANICAL ALIGNMENT
6. MEASUREMENT AND ADJUSTMENT
-MECHANICAL~
7. MEASUREMENT AND ADJUSTMENT
-ELECTRICAL-
8. PREVENTIVE MAINTENANCE
9, TROUBLE SHOOTING CHART
10. SCHEMATIC DIAGRAM
11. PRINTED CIRCUIT BOARD AND PARTS LIST
12. EXPLODED VIEW AND PARTS LIST
13. WARRANTY AND PACKING FOR SHIPMENT
14. MANUAL CHANGE

2. SERVICE DATA
MECHANICAL
FERRITE HEADS:
DIODES:
REEL SIZE:
TAPE WIDTH:
TAPE SPEED:
MOTORS :
FAST WINDING TIME:
wow AND FLUTTER:
OPERATING POSITION:
POWER REQUIREMENT:
WEIGHT =
Four separate heads assembled
in plug in unit.
Four track; Erase 1.8k2/100kHz,
Erase current approx. 30mA
Four track; Record 802/1kHz,
Bias current approx. 3mA(signal 200uF)
Four track; Playback (Forward/Reverse)
1.6k2/1kHz ~64dB/400Hz
SIBO1-02 x2 SIBO1-06 x6
7" maximum NAB reel
Standard 1/4inch tape
7-1/2ips and 3-3/4ips (0.5%)
One- 4/8 pole dual speed hysteresis
synchronous motor for capstan drive.
Two- Six pole eddy current motors
for reel drive.
Approx. 90 seconds for 1200 feet
7" NAB reel
0.06% at 7-1/2ips
0.09% at 3-3/4ips
Wow and flutter measured according
to weighted NAB standard using TEAC
flutter free tape.
Horizontal or vertical.
100/117/200/220/240V AC 50/60Hz 150W
2Qlkg (52 1bs)

SERVICE DATA (conriaueD)
ELECTRICAL
TRANSISTORS:
Tc:
DIODES:
FREQUENCY RESPONSE:
EQUALIZATION:
INPUT:
OUTPUT:
BIAS FREQUENCY:
SIGNAL TO NOISE RATIO:
CROSS TALK REJECTION:
ERASE EFFICIENCY:
2SC1000BL x2 28C971 x2
28C536F x2 28D235 x1
2S8C693F x2
2SA494Y (2SA666IS) x2
2SA572YL4 (2SA666IS) x2
28C733X (2S8C828R) (2S8C536F) x7
TEAC 42709 (LD-3120) x4
TEAC 42710 (LD-3141) x2
SIBO1-02 x5
Zener, 02Z 6.2A x1
Overall from recording INPUT to
playback LINE OUT.
Refer to frequency response limits.
NAB equalization
7-1/2ips 50usec.
3-3/4ips 90usec.
MIC: 6002, 0.25mV
LINE: 50,0002 or more, 0.1V
LINE: 0.3V for load impedance of
10,0002 or more.
PHONES: 82
100kHz push-pull oscillator
464B or more at 3-3/4ips
484B or more at 7-1/2ips
unweighted noise
Channel to channel at 1lkHz/45dB
Adjacent track at 100Hz/40dB
or more.
65dB or more at 7-1/2ips
These specifications are indispensible information and are required
to service the equipment properly. They may differ slightly from
those printed in the advertising brochures or the operation manual.

3. EQUPMENT REQUIRED
For proper adjustment and measurement,
it is recommended that the following
test equipment be available;
FOR MECHANICAL MEASUREMENT
SPRING SCALE:
TEST TAPE:
FLUITER METER:
DIGITAL FREQ. COUNTER:
004 kilo-grams (0v8 1bs) #5086025000
0.300 grams (0°10 oz) #5086026000
TEAC YIT-2003 for 7-1/2ips
TEAC YTT-2002 for 3-3/4ips
Meguro Model MK665B (preferred) or
Sentinel FL-3D-1
Capable of 0 to 5kHz indication
TOOLS: Generali,
2mm nut driver #5086014000
Hex head, Allen wrench #5086021000
FOR ELECTRICAL MEASUREMENT
Fig. 3-1 Allen Wrench
TEST TAPE: TEAC YIT-1003 for 7-1/2ips
TEAC YIT-1002 for 3-3/4ips
SCOTCH 203 and 150 for recording tests
EMPTY REEL TEAC RE-702 (2" huby
TEAC RE-701 (4" hub)
TEST SET: TEAC M-826A test set
BAND PASS FILTER: TEAC M-206A (1kHz)
AC/DC VIVM: General purpose
RESISTOR: Non inductive type 8/1W
OSCILLOSCOPE: General purpose
NOTE: Use of the TEAC M-826A test set is
recommended. This set incorporates a LEVEL
METER, Audio Oscillator, Channel Selecting
Switch, Variable Attenuator, Monitor Speaker §
and Cables.
TEAC M-826A measures the RMS value of the
Voltage (OdB=0.775V).. Characteristics of
this test set are similar to the standard 7
VU-meter. Fig.
3-1 TEAC Test Set
M~826A

4. PARTIAL DISASSEMBLY
TAPE TRANSPORT REMOVAL
AMPLIFIER
Remove power cord and other connecting cords.
Lay the equipment face down on a soft mat.
Remove the two rear cover screws on the top of rear cover.
Remove three upper screws on both sides of the case.
Gently lift the case from the tape transport.
REMOVAL
Remove two screws on both sides of the case.
Slide the amplifier from case.
Fig. 4-1 Case Removal

LEFT TENSION ARM REPLACEMENT
- Unsolder two wires from terminal strip.
- Disconnect one end of the spring.
- Loosen allen screw and spring retaining
pin then lift out tension arm.
IMPORTANT: A special grease (MULTI DIA
$S8-10) must be applied during installa-
tion between the tension arm shaft and
the bushing to maintain proper tension
arm damping.
- To install, reverse the previous procedures.
RIGHT TENSION ARM REPLACEMENT
- Disconnect one end of the spring.
- Loosen allen screw retaining the tension
arm shaft, and gently lift out the ten-
sion arm.
- Apply "MORICOTE" (graphite-molybdenum
based) to tension arm shaft and bushing
during installation.
~ After installation, check tension arm
operation, It should operate freely and
the thrust clearance should be minimum
(secure but not binding).
REEL MOTOR REPLACEMENT
- Using hex head wrench, loosen the two
screws on the counter belt pulley.
Remove pulley (right turntable only).
- Remove the rubber insert, then remove
the three screws holding reel table
to motor, Lift out the reel table,
shim and spacer.
- Remove the three screws holding the
reel motor to the mount.
- Unsolder four wires connecting the
reel motor and remove motor from panel.
~ Cut the four wires connecting the reel motor
approx. 1" above the terminal.
~ Remove the four screws mounting the motor.
- To reinstall reel motor, reverse above pro-
cedures. Use the wire remaining on the
terminal for a guide in re-wiring the new
motor.
L—-Fig. 4-2 Left Tension Arm——
&F
eS
o>
Lange: 4-3 Right Tension Arm —
CAUTION: While replacing, be careful not
vend the brake bands. Do not get ofl on
the brake drum.
Fig. 4-4 Reel Motor ————

CAPSTAN ASSEMBLY REPLACEMENT
- Remove capstan dust cap on the front panel.
- Remove two screws mounting the thrust plate
and pull away from the chassis.
- Remove capstan belt.
- Loosen two allen screws in the capstan fly-
wheel and remove the flywheel.
- Remove three screws mounting the capstan
assembly and lift the assy upward.
~ Reverse the above procedures when install-
ing the capstan assembly.
- During installation, apply a thin applica-
tion of grease to the panel inside the
thrust plate.
CAUTION: A clearance of approx. 0.5mm must
be maintained between the flywheel and cap-
stan assembly.
CAPSTAN MOTOR REPLACEMENT
- Remove the fan by loosening two hex screws.
~ Remove the capstan belt, PC board and cap-
stan pulley by loosen two hex set screws.
~ Cut the six wires connecting the motor on
the PC board.
~ Remove the three slotted screws (studs bolt).
~ Gently fold capstan motor assy and remove the
four screws holding the motor on the pulley
side. Then remove the four motors holding
screws on the fan side.
- To reassemble, reverse the procedures.
NOTE: After motor replacement, check posi-
tion of capstan pulley on shaft for proper
alignment with belt guide.
Check to make sure the pinch roller installing.
If is loose, open the slot slightly.

HEAD REPLACEMENT
NOTE: Heads can be replaced individually or as a complete assembly.
Azimuth adjustment (electronic) is not to be performed until all
mechanical alignments have been performed. After replacing the heads,
proceed to the next page for mechanical alignment.
CAUTION: All power must be removed from the unit when replacing
heads to prevent transient pulses from passing through the heads.
These may cause strong magnetization of the head material or damage
the delicate winding.
HEAD ASSEMBLY REPLACEMENT
~ Remove the head housing cover by loosening
two hex screws on top of cover.
~ Remove the four mounting screws indicated by
the arrows in the. diagram.
~ Slide the assy out from the plug.
- Fit the original shielding plate onto the new
head assy.
- Slide the new assembly onto the unit and se-
cure the four screws.
- Proceed to the next page for mechanical align-
ment procedures.
INDIVIDUAL HEAD REPLACEMENT
NOTE: All of the heads are individually
mounted on the top base plates of head
assembly for easy accessibility and
servicing.
- Remove head housing cover to expose head assy.
~ To replace a single head, a special 2mm nut
driver is required.
~- Remove the two nuts on the defective head
through the, access hole provided to release
the head from the mounting plate.
- Note the position of the head's wires on the
circuit board and unsolder the defective head.
- Using figure for reference, connect the new
head to the circuit board.
- Head installation mounting provides for either
left or right positioning.
- Determine the proper position by adjusting the
nuts to obtain a 90° angle between the tape
and the head.
~ Proceed to the next page for mechanical align—
ment procedures. '-Fig. 4-8 Individual Head—

u
5. HEAD MECHANICAL ALIGNMENT
NOTE: Head alignment is adjusted at the factory to very critical
tolerances, Normally head assembly replacement will require only
minor alignments or adjustments. Complete readjustment should
only be necessary after an individual head is replaced.
The adjustments are made as follows’:
ERASE HEAD: The erase head pole should be above the edge of a
threaded tape by the width of a heavy pencil line. Adjust the three
screws indicated to obtain this height.
RECORD HEAD: The record head pole should be above the edge of a
threaded tape by the width of a thin pencil line. Adjust the two
screws indicated to obtain this height.
IMPORTANT: After completing the
height adjustment make certain
head surfaces are paraliel with
tape guide surfaces when viewed
from the sidey
PLAYBACK HEADS: The reverse playback head pole should be even with
the bottom of the tape and the forward play head pole should be even
with the top of the tape. Adjust the screws indicated.
NOTE: Refer to figure for locating the screws used in the preceding
alignments and azimuth adjustments are given in the section on
MEASUREMENT AND ADJUSTMENT -ELECTRICAL~.
econo REVERS FORWARD
oxwesce
Fig. 5-L Head Mechanical Alignment

TAPE TRANSPORT PARTS LOCATION
A-60170GSL
-REAR-
TENSION RESISTOR:
FREQUENCY _™
SEL SW
rE
PLAY
RL
CAPSTAN
:
;
is
es
Hoes
6
Se
:
DELAY
RL
. i
IMPEDANCE
CAPSTAN
a
j
enn
x
e
FLYWHELL
;
7
FLYWHELL
Ks
HEAD SEL RL
e i NOTE
SW : SWITCH
D-0469
Ka
P
K
ae
‘6 :
SENSING | REVERSE RL | FAST FORWARD RL SEL ‘SEL!
Ks CAPSTAN SOL RL :RELAY
ithe
SOL
?
SOLENOID

1B
PINCH ROLLER PRESSURE MEASUREMENT
FLUTTER
6. MEASUREMENT AND ADJUSTMENT
-MECHANICAL-
NOTE: The TEAC GSL series tape deck uses a highly reliable three
motor drive solenoid operated system and should require a minimum
of mechanical maintenance or adjustment. These adjustments are
made at the factory, Readjustment should only be required after
many hours of operation or component replacement.
capstan
NOTE: Pinch roller pressure is supplied FINCHER,
by pinch roller pressure spring only and 4
it is therefore most important that the TOOT ME TOE SPRING SCALE
solenoid plunger has fully bottomed
before taking pressure measurement.
- Block the automatic shut-off arm in
the ON position.
- Attach a suitable spring scale to the
pinch roller shaft.
- Place the unit in the play mode ( pm )
and holding the scale as illustrated,
slowly draw it away from the pinch
roller stops rotating.
- The spring scale should indicate
- If adjustment is necessary, adjust the
double nuts on the capstan solenoid
plunger.
L_Fig. 6-2 Pressure Adjustment
& TAPE SPEED MEASUREMENT
Flutter and tape speed should be measured in playback mode using a TEAC
flutter free tape YIT-2003-2002. Connect test equipment to unit
as shown in the figure. Measurement of flutter should be made in
accordance with NAB standards. Values obtained with different standards
or equipment cannot be compared.
Flutter should not exceed.
7-1/2ips : 0.06%
3-3/4ips : 0.09%
The tape speed should be measured using TEAC
flutter free tape, model YTTI-2003:2002.
These tapes contain a highly accurate 3 kHz
tone. The indicated frequency should be 2985
3015 kHz for all speeds, both directions. a Or
These figures apply to any tape position and
direction (such as full take-up reel, full
supply reel or about mid point). Fig. 6-3 Equipment Set-up -—-

BACK TENSION
NOTE: Be sure the full required line voltage is applied and that
the unit is set to the proper line frequency.
Forward —Regular-
1. Block the shut-off arm in the ON position.
2. Place TAPE switch to REGULAR position.
3. Place an empty RE-702(5cm hub) and spring
scale on left reel table.
4. Rotate the reel and wind several turns of
string around the hub.
5. Place the unit in the ( P ) play mode.
6. Pull the scale away from the reel against
the motor torque, with a smooth steady
motion. The spring scale reading 84092
grams (210v230 g-cm).
7
BACK TENSION: AKE UP TORQUE
TARE UP TO#GUE:BACK TENSION
7. If necessary, adjust slider tabs B of R4 ue Ge
resistor until correct tension is obtained, ‘Fig. 6-4 Reel Motor Torque
Measurement
Forward -Thin-
8. Depress the TAPE tension switch to THIN position.
9. Repeat above steps, the spring scale reading should 72¥80 grams
(1807200 g-cm). If is not, adjust the R5 resistor. After R5
resistor has been adjusted, set the TAPE tension to REGULAR position.
REVERSE FORWARD
BACK TAKE UP.
TENSION TENSION
CHASSIS
R FORWARD REVERSE
os UP
TENSION TENSION
Fig. 6-2 Adjustable Tension Resistor

15
TAKE-UP TORQUE MEASUREMENT & ADJUSTMENT
Forward
1s
Place
the
empty
reel
RE-701
and
attached
spring
scale
on
the
right
reel
table.
2. Set the TAPE switch to REGULAR position.
3.
Place
the
unit
in
the
(
p
)
play
mode.
Allow
the
rotation
of
the
reel
to
slowly
draw
the
scale
toward
the
hub.
4,
Hold
the
spring
scale
with
enough
force
to
allow
a
steady
reading
135%150
grams
(340%370
g-cm).
5. If adjustment is necessary, R3 slider tab A.
Reverse
6.
Place
the
empty
reel
RE-701
and
spring
scale
on
the
left
reel
table.
7.
Pressing
(
<
)
play
button,
and
allow
the
rotation
of
the
reel
to
slowly
draw
the
scale
toward
the
hub.
8. The spring scale should read 190¥200 grams (470%500 g-cm).
9.
If
torque
is
incorrect,
make
adjustment
of R4
resistor
slider
tab
A.
PLAY -REC
RIGHT
R3 3000
ACIOOV
fe
comme) M0429
Fig. 6-7 Reel Motor Partial Circuit —————~———_

FAST WIND BACK TENSION ADJUSTMENT
1. Load a full 1800 feet 7" reel of tape
on the right reel table and an empty
reel on left reel table and set the
TAPE switch to REGULAR position.
2. Depress the ( < ) and the FAST button
simultaneously.
3. At this time observe the right tension. .
Adjust R7 so that the arm moves approx. Lpig, 6-8 Fast Wind Check:
i" to the right and remains there.
4, Interchange the both reels, full reel on the right and empty reel on
the left reel.
5, Repeat above step 2, the full reel should start rotating quickly and
smoothly.
6. Repeat above procedure until the desired results are obtained.
BRAKE TORQUE MEASUREMENT & ADJUSTMENT
Brake adjustments are made with no power, applied to the unit.
1. Place an empty 10cm(4") hub reel and spring scale on left reel table.
2. Wind several turns of string counter clockwise around the hub.
3. Pull the spring scale away from the reel. Take a reading only when
the reel is in steady motion since the force required to overcome
static friction will produce a false, excessively high initial
reading.
The reading should be 300 grams (1500 g-cm +50 g-cm).
. If adjustment is required, adjust the adjustable nut attached to the
brake spring bolt for the proper brake torque.
6. To check and adjust the right reel brake repeat all steps as described
for left reel with the exception that all directions of rotation are
clockwise.
un
IMPORTANT: The difference in torque between the right and left brake
should be kept within 10 grams (50 g-cm).
ES TEN, BRAKE ADJUSTMENT
Fig. 6-9 Torque Measurement Fig. 6-10 Torque Adj. Location

Md
7. MEASUREMENT AND ADJUSTMENT
-ELECTRICAL-
GENERAL NOTICE
Before performing any maintenance on this unit, all metal
parts that the tape will come into contact with must be
cleaned and demagnetized.
It is important that the unit is set for the proper voltage
and frequency for your locality.
Standard test tapes and test equipment must be used when per
forming maintenance to insure reliable results.
Procedures for checks and adjustments, unless otherwise indi-
cated, are for the left channel at 7~1/2ips. The same pro-
cedures are to be applied to the right channel and the other
tape speeds.
All controls mentioned in this book will be. printed in bold
letters and will be exactly as they appear on the unit.
Double designated symbol numbers refer to left channel/right
channel.
THD: Yhird harmonic distortion.
Value of "dB" in the text refers to 0dB=0.775V, except where
specified. If a level meter or an AC VIVM calibrated to 0dB
=1V is to be used, appropriate compensation should be made
by adding approximately 2 dB.
When not using the TEAC test set M-826A, connect a 10 kn load
across the OUTPUT jacks to assure that 0dB=0.775V with the
VIVM.
POWER SUPPLY CIRCUIT CHECK
Measure DC voltage of rectifier
circuit at R-309 for approximately
23 volts. If proper voltage is
not present, adjust VR~304.
71

PLAYBACK PERFORMANCE
Q@
‘vmiovse! Viuoes202
: 9 J
Giescaos
340 O aa
PLAYBACK EQ ian
Fig. 7-1 Playback Circuit Simplified
PLAYBACK HEAD AZIMUTH ADJUSTMENT
Coarse Adjustment
1.
2.
3.
4.
Connect the test set to either LINE OUT jack.
Thread a TEAC test tape YTT-1003 on the unit with MONITOR switch
to TAPE position.
Depress forward button ( p ) and play the 15 kHz test tone in
section 2 of the test tape.
Slowly rotate the azimuth screw until maximum indication is indicated
on the level meter.
NOTE: If during playback, a slight pressure on the heads re-
sults in a rise of the reading of the level meter, head MECHANICAL
ALIGNMENT readjustments should be accomplished.
Fine Adjustment
CAUTION: Do not make large corrections during fine adjustment,
turn the screw 1/4 of a revolution or less.
It is absolutely essential to accomplish the coarse adjustment
before using this method to avoid phase errors larger than 45°.
. Connect the test equipment as shown in fugure.
. Play a 10 kHz signal and adjust the
azimuth screw until the oscilloscope
shows that the signals are less than
45° in phase.
Secure the azimuth adjustment screw
with LOCTITE and apply the above pro-
cedure to the remain playback head.
Fig. 7-2 Fine Adj. Set-up—

19
SPECIFIED OUTPUT LEVEL SET
10.
i.
IMPORTANT: Unless otherwise specified, the EQ/LEVEL switch must
always be in the HIGH position during measurement and adjustment.
Play the 400 Hz tone in section 1 of the test tape. This tone is
recorded at operating reference level (1% of the THD level).
Turn the OUTPUT controls fully clockwise, and adjust VR-103/203 for
-2 dB reading on the test set.
Then turn OUTPUT controls(c.c.w.) until a -8 dB reading is obtained
on the test set. If equal VU meter reading cannot be obtained in
step 11, readjust VR-103/203 slightly.
OUTPUT
NOTE: This is the specified output
level setting. Do not disturb this d
setting until the remaining adjust- .
ments have been completed.
ax
5 mis. ote
Fig. 7-3 Specified Set Position
VU METER CALIBRATION -PLAYBACK-
12.
While playing the 400 Hz tone (1% THD) in section 1 of the test
tape, adjust VR-104/204 for a reading of 0 VU on the VU meter.
The EQ/LEVEL switch should be in NORMAL position.
HIGH level check: While playing back 400 Hz (operating reference
level) signal, move the EQ/LEVEL switch from HIGH to NORMAL posi-
tion, The VU meter should decrease 3 dB. This is a performance
check only. After checking, return EQ/LEVEL switch to HIGH
position.
FREQUENCY RESPONSE AND THE PLAYBACK EQUALIZATION ADJUSTMENT
13.
14.
15.
16.
17.
18.
Play section 3 of TEAC Test Tape YTT-1003 at 7-1/2ips (which was
recorded at 10 dB below the operating reference level).
Compare the readings with the response limits given in figure.
Adjust the equalization trimmer resistors VR-101/201 to obtain the
flattest possible response within +2 dB limits between 7.5 kHz and
15 kHz.
Play section 3 of TEAC Test Tape YIT-1002 at 3-3/4ips.
Compare the readings with the response limits given in figure below.
Adjust the equalization trimmer resistors VR-101/201 to obtain the
flattest possible response within +2 dB limits between 7.5 kHz and
10 kHz.
NOTE: During reverse play, the readings should be almost identical
with forward play. However, do not made any adjustments of the
trimmers during reverse play
7-3

50 100 600K eK S eoete
Fig.
7-4
Frequency
Response
Limits
-Playback-
0 mK PeiPK WOK 20K
Nite one
Fig. 7-5 Equalization Curves -Playback-
SIGNAL TO NOISE RATIO CHECK
NOTE:
Values
given
are
obtained
using
an
unweighted
level
meter
while
the
supply
and
take-up
motors
have
voltage
applied
but
are
not
rotating.
The
OUTPUT
control
should
be
at
specified
output
position.
1.
Thread
a
tape
on
the
unit,
leaving
the
tape
outside
the
capstan
and
pinch
roller.
Tension
arm
should
be
in
ON
position.
2.
Place
the
unit
in
the
PLAY mode
(
pb
)
(the
tape
will
not
move).
4.
The
level
meter
connected
to
the
LINE
QUT
jacks
should
indicate
as
listed
below.
vwvy v v
-56dB/7-1/2ips
-54dB/3-3/4ips
For example: -56 dB indicated corresponds
to a signal to noise ratio of 48 dB (dif-
ference between residual noise -56 dB and
the specified output level of -8 dB for
1% THD).
For a 3% THD signal to noise ratio, 6 dB
is
added,
giving
54
dB
(3%
THD
is
6
dB
—e
a
above
1%
THD
level).
Fig.
7-6
Signal
&
Noise—
Computation
7-4